Best Time To Plant Kohlrabi In Missouri

Missouri’s variable weather suggests planting kohlrabi in April, after the soil has warmed to at least 40 degrees. But finding the best time to plant kohlrabi in missouri isn’t just about one month. It’s about working with your local frost dates and the plant’s love for cool weather.

Kohlrabi is a fast-growing vegetable from the cabbage family. It thrives in spring and fall. In Missouri, you have two windows to grow it. This guide covers both seasons. You’ll learn exact dates, soil prep, and care tips.

The best time to plant kohlrabi in missouri is early spring, as soon as the soil can be worked. For most of the state, that means late March to mid-April. A second planting in late summer gives you a fall harvest.

Kohlrabi seeds germinate in soil temps between 40°F and 85°F. But they grow best when temps stay between 60°F and 70°F. If it gets too hot, the bulbs become woody and tough. If it’s too cold, growth slows down.

Spring Planting Window For Missouri

Missouri spans USDA hardiness zones 5b to 7a. Your exact planting date depends on your zone. Here’s a simple breakdown:

Northern Missouri (zones 5b-6a): Plant seeds outdoors from March 25 to April 10
Central Missouri (zone 6b): Plant from April 1 to April 15
Southern Missouri (zones 6b-7a): Plant from March 20 to April 5

You can also start seeds indoors 4-6 weeks before your last frost date. Transplant seedlings when they have 3-4 true leaves. Harden them off for a week before moving them outside.

Fall Planting Window For Missouri

Fall kohlrabi often tastes sweeter because cool weather boosts sugar content. Plant seeds 8-10 weeks before your first fall frost. For most of Missouri, that means:

Northern Missouri: Plant from August 1 to August 15
Central Missouri: Plant from August 10 to August 25
Southern Missouri: Plant from August 20 to September 5

Fall crops need consistent watering. August heat can dry out soil fast. Mulch around plants to keep roots cool and moist.

Understanding Missouri’s Climate Zones

Missouri has a humid continental climate in the north and a humid subtropical climate in the south. Summers are hot and humid. Winters can be cold but not extreme. This mix affects when you plant.

Last Frost Dates By Region

Knowing your last spring frost date is key. Here are average dates:

Northern MO (like Kirksville): April 20-30
Central MO (like Columbia): April 10-20
Southern MO (like Springfield): April 1-10
Bootheel (like Sikeston): March 25-April 5

Kohlrabi can handle light frosts. But a hard freeze below 28°F will damage young plants. Use row covers if a late freeze is forecast.

First Frost Dates For Fall Planting

Fall planting relies on first frost dates. Average first frosts are:

Northern MO: October 1-10
Central MO: October 10-20
Southern MO: October 20-31
Bootheel: November 1-10

Kohlrabi matures in 45-60 days depending on variety. Count backward from your first frost date to find your planting window.

Soil Preparation For Kohlrabi

Kohlrabi grows best in loose, fertile soil with a pH between 6.0 and 7.5. Test your soil before planting. Missouri soils are often clay-heavy or acidic. Amend as needed.

Steps To Prepare Your Garden Bed

Clear all weeds and debris from the bed
Loosen soil to a depth of 8-10 inches
Mix in 2-3 inches of compost or well-rotted manure
Add a balanced fertilizer like 10-10-10 at 1 pound per 100 square feet
Rake the bed smooth and water it well

If your soil is heavy clay, consider raised beds. Kohlrabi bulbs need room to expand. Compacted soil leads to misshapen bulbs.

Soil Temperature Check

Use a soil thermometer to check temp at 2 inches deep. For spring planting, wait until soil reaches 40°F. For fall planting, soil should be below 85°F. If it’s too hot, wait for cooler weather.

You can speed up spring warming by covering beds with black plastic for a week before planting.

How To Plant Kohlrabi Seeds

Kohlrabi can be direct-seeded or transplanted. Direct seeding is simpler and works well for fall crops. Transplants give you a head start in spring.

Direct Seeding Method

Sow seeds 1/4 to 1/2 inch deep
Space seeds 2 inches apart in rows 12-18 inches apart
Water gently to avoid washing seeds away
Thin seedlings to 4-6 inches apart when they have 2 true leaves
Keep soil moist until seeds germinate (5-10 days)

Thinning is important. Crowded kohlrabi produces small bulbs. Use scissors to snip extra seedlings at soil level. Pulling them can disturb roots.

Transplanting Seedlings

If you start seeds indoors, use biodegradable pots. Kohlrabi roots are sensitive to disturbance. Plant the whole pot in the ground.

Harden off seedlings over 5-7 days
Dig holes 4-6 inches apart
Set seedlings slightly deeper than they were in pots
Water thoroughly after planting
Apply a starter fertilizer high in phosphorus

Transplants often mature 1-2 weeks faster than direct-seeded plants. This helps you beat the summer heat.

Caring For Kohlrabi Plants

Kohlrabi is relatively low-maintenance. But consistent care prevents common problems. Focus on water, nutrients, and pest control.

Watering Requirements

Kohlrabi needs 1-1.5 inches of water per week. Inconsistent watering causes bulbs to crack or become woody. Use drip irrigation or soaker hoses to keep foliage dry.

Water deeply 2-3 times per week
Mulch with straw or grass clippings to retain moisture
Reduce watering as bulbs mature to prevent splitting

During dry spells in Missouri summers, you may need to water daily. Check soil moisture by sticking your finger 2 inches deep. If it feels dry, water.

Fertilizing Schedule

Kohlrabi is a heavy feeder. Apply a nitrogen-rich fertilizer 3-4 weeks after planting. Side-dress with compost tea or fish emulsion every 2 weeks.

Use a 20-20-20 fertilizer at half strength
Avoid too much nitrogen late in growth; it can cause leafy growth over bulb development
Stop fertilizing 2 weeks before harvest

If leaves turn yellow, your plant may need more nitrogen. If bulbs are small, check phosphorus levels.

Common Pests And Diseases

Missouri gardens face several pests that attack kohlrabi. Watch for these:

Cabbage worms: Small green caterpillars that chew holes in leaves. Use row covers or spray with Bt (Bacillus thuringiensis)
Aphids: Tiny insects that suck sap. Blast them off with water or use insecticidal soap
Flea beetles: Small jumping beetles that create shot holes in leaves. Use diatomaceous earth or neem oil
Clubroot: A soil-borne disease that causes swollen roots. Rotate crops and avoid planting in infected soil

Rotate kohlrabi with non-cruciferous crops each year. Don’t plant it where cabbage, broccoli, or kale grew the previous season.

Harvesting Kohlrabi At The Right Time

Harvest kohlrabi when bulbs are 2-3 inches in diameter. Larger bulbs become tough and fibrous. Check size every few days as harvest approaches.

Signs Your Kohlrabi Is Ready

Bulb feels firm and smooth
Leaves are still green and healthy
Bulb is about the size of a tennis ball
Stem is crisp and snaps easily

Pull the entire plant from the ground. Cut off leaves and roots. Store bulbs in the refrigerator for up to 2 weeks. Leaves are edible too; use them like collard greens.

Harvesting In Hot Weather

If a heat wave hits, harvest kohlrabi early. Even slightly small bulbs are better than woody ones. You can also shade plants with a row cover to delay bolting.

Bolting happens when kohlrabi gets stressed by heat. The plant sends up a flower stalk. Once it bolts, the bulb becomes inedible. Harvest immediately if you see flower buds.

Best Kohlrabi Varieties For Missouri

Choose varieties that mature quickly and tolerate temperature swings. Here are top picks for Missouri gardens:

Early White Vienna: Matures in 50-55 days. Classic white-green bulb. Good for spring and fall
Purple Vienna: Matures in 55-60 days. Purple skin, white flesh. More cold-tolerant
Korridor: Matures in 45-50 days. Hybrid variety with uniform bulbs. Resists woodiness
Superschmelz: Matures in 60-65 days. Giant bulbs up to 10 inches. Slow to become woody
Kolibri: Matures in 50-55 days. Purple skin. Sweet flavor. Good for fall planting

For spring planting, choose fast-maturing varieties like Early White Vienna. For fall, try Superschmelz or Purple Vienna for better cold tolerance.

Extending The Growing Season

You can stretch your kohlrabi harvest by using season extenders. This is helpful in Missouri where spring and fall are short.

Using Row Covers

Floating row covers protect plants from frost and pests. They let light and water through but keep bugs out. Use them in early spring and late fall.

Lightweight covers: Add 2-4°F of frost protection
Medium-weight covers: Add 4-6°F of protection
Remove covers when temps rise above 85°F to prevent overheating

Row covers also speed up growth by trapping heat. Your kohlrabi may mature 1-2 weeks faster under covers.

Succession Planting

Plant a new batch of seeds every 2-3 weeks during spring and fall. This gives you a continuous harvest instead of one big crop.

Spring: Plant seeds March 20, April 5, and April 20
Fall: Plant seeds August 1, August 15, and August 30

Stop planting when daytime highs regularly exceed 85°F. Kohlrabi won’t form good bulbs in extreme heat.

Common Mistakes To Avoid

Even experienced gardeners make errors with kohlrabi. Here are pitfalls to skip:

Planting too late in spring: Kohlrabi needs cool weather. If you plant in May, heat will ruin the bulbs
Overcrowding: Thin seedlings to 4-6 inches apart. Crowded plants produce tiny bulbs
Inconsistent watering: Dry spells followed by heavy rain cause bulbs to crack
Skipping soil test: Kohlrabi needs specific pH and nutrients. Test soil every 2 years
Harvesting too late: Check bulbs daily once they reach 2 inches. Bigger isn’t better

If you make a mistake, don’t worry. Kohlrabi grows fast. You can replant in a few weeks for a second chance.

Frequently Asked Questions

Can I Plant Kohlrabi In July In Missouri?

July is usually too hot for kohlrabi in Missouri. Soil temps above 85°F prevent good germination and bulb formation. Wait until August for fall planting.

How Deep Should I Plant Kohlrabi Seeds?

Sow seeds 1/4 to 1/2 inch deep. Cover lightly with soil and keep moist. Deeper planting may prevent germination.

Does Kohlrabi Need Full Sun?

Yes, kohlrabi needs at least 6 hours of direct sunlight daily. Partial shade is okay in hot summer areas but may slow growth.

Can I Grow Kohlrabi In Containers?

Yes, use a pot at least 12 inches deep and wide. Choose a compact variety like Early White Vienna. Ensure good drainage and water frequently.

Why Are My Kohlrabi Bulbs Not Forming?

Bulb failure is usually due to heat stress, overcrowding, or lack of nutrients. Check soil temperature, thin plants, and fertilize with a balanced product.

Final Tips For Missouri Gardeners

Kohlrabi is one of the easiest cool-season crops to grow. It’s also one of the most rewarding. You get a crisp, mild-flavored bulb that’s great raw or cooked.

Start with a small patch your first season. Note how your garden responds. Adjust planting dates based on your microclimate. A south-facing slope warms faster than a low-lying area.

Keep a garden journal. Write down planting dates, weather patterns, and harvest results. Over time, you’ll dial in the perfect schedule for your spot.

Missouri’s weather is unpredictable. But with the right timing, you can enjoy fresh kohlrabi from spring through fall. Plant early, water well, and harvest at the right size. Your taste buds will thank you.